<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>动态广告</title>
</head>
<body>
    <img src="img/1.jpg" id="A1" width="20%"/>
</body>

    <script>
      //定时器，1秒后显示广告图片
        setTimeout(function (){
          let img = document.getElementById("A1");
          img.style.display="block";
        },1000);

      //1秒后隐藏图片
      setTimeout(function (){
        let img = document.getElementById("A1");
        img.style.display="none";
      },2000);
    </script>
</html>